Prosecutors have called for the death sentence for Nguyen Xuan Son, former Chairman of the State-owned oil and gas group PetroVietnam, and a life sentence for his counterpart Ha Van Tham at OceanBank, as the dramatic multi-million-dollar graft trial continues in Hanoi.

Son served as Chairman of the Board at PetroVietnam from 2014 before he was transferred to the Ministry of Industry of Trade by a decision signed by former Prime Minister Nguyen Tan Dung dated July 19, 2015. He was arrested in the same month and is charged with embezzlement, abuse of power, and deliberately violating State regulations on economic management.

The 55-year-old, who had held various executive positions at PetroVietnam since 2003, is accused of pocketing around $11 million from the bank. He was CEO of OceanBank between 2008 and 2010, during which time PetroVietnam became a major shareholder.

Tham, the former Chairman of OceanBank, faces similar charges as well as “breaking regulations on lending activities at credit institutions.” Other former bank executives face up to 27 years behind bars.

The bank gave $69 million in interest payment that exceeded the rate set by the State Bank of Vietnam (SBV) to more than 50,000 individuals and nearly 400 companies and institutions, including three subsidiaries of PetroVietnam, according to prosecutors. Although Tham said the higher rates were offered to attract customers to keep the bank afloat and that they had paid off with profits, prosecutors said the crime “seriously affected the monetary market.”

A police statement said that $3.4 million in excess interest was given to the PetroVietnam Exploration and Production Corporation, $852,000 to the Binh Son Oil Refinery (BSR), and $1 million to VietsovPetro, a joint venture between PetroVietnam and Russia.

The trial opened in Hanoi on August 28 and is scheduled to last 20 days. It could go down as the biggest in Vietnam's history, with 51 bankers and businesspeople in the dock.

OceanBank was founded in 1993 with a 20 per cent stake from the Ocean Group conglomerate, which also invests in hospitality, securities, media, and retail. In April 2015, the central bank took over the bank and put major lender VietinBank in charge. The bank’s new Chairman said in a statement posted on its website in January that its operation had been “profitable” over the past two years.

Over the last two weeks, police have arrested or put under house four other former or current senior executives of PetroVietnam and a former Deputy Governor of the SBV, who oversaw bad debts at credit institutions, for their role in the case.